Doepfer

I programmed a patch with my beautifully tuned VCOs, tonight.  When I decided to use the A155 through a 156 to drive it, I noticed a significant voltage drop and I had to apply a voltage from the 176 to bring it back in tune with my other synth.  Why should this be?

I have also noticed that running the CV from the quantizer through either the dual or the VC Slew also caused a voltage droop, regardless of how low the slew setting is.  

  Can anyone explain why this might be happening.